Composite direct collection XML mappings map a collection of simple types (String, Number, Date, etc.) to and from a sequence of composite XML nodes.
Composite direct collection XML mappings can be used in the following scenarios:
Setting the XPath: TopLink XML mappings make use of an XPath statement to find the relevant
data in an XML document. The XPath statement is relative to the context node specified in the descriptor.
The XPath may contain node type, path, and positional information. The XPath is specified on the
mapping using the setXPath method.
The following XPath statements may be used to specify the location of XML data relating to an object's name attribute:
| XPath | Description |
|---|---|
| @tasks | The "@" character indicates that the node is an attribute. This XPath applies only to the single attribute node case; each member of the collection is mapped to a single node. |
| tasks/@task | The "@" character indicates that the node is an attribute. The information is stored in the attribute node of the tasks element. |
| text() | "text()" indicates that the node is a text node. In this case the task value in the text node belongs to the context node. |
| tasks/text() | The task information is stored in the text node of the tasks element. |
| tasks/task/text() | The XPath statement may be used to specify any valid path. |
| task[2]/text() | The XPath statement may contain positional information. In this case the task information is stored in the text node of the second occurrence of the task element. |
Mapping to a Single Text Node: By default, TopLink maps each member of a collection
to it's own node. It is possible, however, to mapping a collection to a single node; here the contents of
the node is treated as a space-separated list. This behavior is set on the mapping using the
setUsesSingleNode method, with 'true' as the parameter.
XML Schema
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:element name="employee" type="employee-type"/>
<xsd:complexType name="employee-type">
<xsd:sequence>
<xsd:element name="tasks" type="tasks-type"/>
</xsd:sequence>
</xsd:complexType>
<xsd:simpleType name="tasks-type">
<xsd:list itemType="xsd:string"/>
</xsd:simpleType>
</xsd:schema>
Code Sample
XMLCompositeDirectCollectionMapping tasksMapping = new XMLCompositeDirectCollectionMapping();
tasksMapping.setAttributeName("tasks");
tasksMapping.setXPath("tasks/text()");
tasksMapping.setUsesSingleNode(true);
Specifying the Content Type of a Collection: By default, TopLink will treat the node values read in by a composite direct collection XML mapping as objects of type String. You can override this behavior by specifying the type of the collection's contents.
XML Schema
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:element name="employee" type="employee-type"/>
<xsd:complexType name="employee-type">
<xsd:sequence>
<xsd:element name="vacation" type="xsd:string" maxOccurs="unbounded"/>
</xsd:sequence>
</xsd:complexType>
</xsd:schema>
Code Sample
XMLCompositeDirectCollectionMapping tasksMapping = new XMLCompositeDirectCollectionMapping();
tasksMapping.setAttributeName("vacationDays");
tasksMapping.setXPath("vacation/text()");
tasksMapping.setAttributeElementClass(Calendar.class);
Mapping to a List of Unions:
XML Schema
<?xml version="1.0" encoding="UTF-8"?>
<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema">
<xsd:element name="vacation" type="listOfUnions"/>
<xsd:simpleType name="listOfUnions">
<xsd:list>
<xsd:simpleType>
<xsd:union memberTypes="xsd:date xsd:integer"/>
</xsd:simpleType>
</xsd:list>
</xsd:simpleType>
</xsd:schema>
Code Sample
XMLCompositeDirectCollectionMapping mapping = new XMLCompositeDirectCollectionMapping();
mapping.setAttributeName("myattribute");
XMLUnionField field = new XMLUnionField("listOfUnions/text()");
mapping.addSchemaType(new QName(url,XMLConstants.INT));
mapping.addSchemaType(new QName(url,XMLConstants.DATE));
mapping.setField(field);
mapping.useSingleElement(false);
More Information: For more information about using the XML Composite Direct Collection Mapping, see the "Understanding XML Mappings" chapter of the Oracle TopLink Developer's Guide.
| Modifier and Type | Field and Description |
|---|---|
| private boolean | |
| private boolean | |
| private boolean | |
| private boolean | |
| private boolean | |
| private AbstractNullPolicy | |
| protected transient Object | nullValue
Support specification of the value to use for null. |
| protected boolean | |
| private AbstractNullPolicy |
| Access | Constructor and Description |
|---|---|
| public |
| isCDATA | back to summary |
|---|---|
| private boolean isCDATA | |
| isCollapsingStringValues | back to summary |
|---|---|
| private boolean isCollapsingStringValues | |
| isDefaultEmptyContainer | back to summary |
|---|---|
| private boolean isDefaultEmptyContainer | |
| isNormalizingStringValues | back to summary |
|---|---|
| private boolean isNormalizingStringValues | |
| isWriteOnly | back to summary |
|---|---|
| private boolean isWriteOnly | |
| nullPolicy | back to summary |
|---|---|
| private AbstractNullPolicy nullPolicy | |
| nullValue | back to summary |
|---|---|
| protected transient Object nullValue Support specification of the value to use for null. | |
| reuseContainer | back to summary |
|---|---|
| protected boolean reuseContainer | |
| wrapperNullPolicy | back to summary |
|---|---|
| private AbstractNullPolicy wrapperNullPolicy | |
| XMLCompositeDirectCollectionMapping | back to summary |
|---|---|
| public XMLCompositeDirectCollectionMapping() | |
| convertDataValueToObjectValue | back to summary |
|---|---|
| public Object convertDataValueToObjectValue(Object value, Session session, XMLUnmarshaller unmarshaller) Implements org. INTERNAL
| |
| convertObjectValueToDataValue | back to summary |
|---|---|
| public Object convertObjectValueToDataValue(Object value, Session session, XMLMarshaller marshaller) Implements org. INTERNAL
| |
| getNullPolicy | back to summary |
|---|---|
| public AbstractNullPolicy getNullPolicy() Implements org. Doc from org. Get the AbstractNullPolicy from the Mapping.
| |
| getNullValue | back to summary |
|---|---|
| public Object getNullValue() Implements org. PUBLIC: Allow for the value used for null to be specified. This can be used to convert database null values to application specific values, when null values are not allowed by the application (such as in primitives). Note the default value for NULL is used on reads, writes, and query SQL generation
| |
| getReuseContainer | back to summary |
|---|---|
| public boolean getReuseContainer() Implements org. Return true if the original container on the object should be used if present. If it is not present then the container policy will be used to create the container.
| |
| getWrapperNullPolicy | back to summary |
|---|---|
| public AbstractNullPolicy getWrapperNullPolicy() Implements org. Doc from org. Get the Wrapper NullPolicy from the Mapping.
| |
| getXPath | back to summary |
|---|---|
| public String getXPath() Get the XPath String
| |
| initialize | back to summary |
|---|---|
| public void initialize(AbstractSession session) throws DescriptorException Overrides org. INTERNAL: Initialize the mapping.
| |
| isCDATA | back to summary |
|---|---|
| public boolean isCDATA() Implements org.
| |
| isCollapsingStringValues | back to summary |
|---|---|
| public boolean isCollapsingStringValues() Implements org. PUBLIC: Returns true if this mapping should collapse all string values before adding them to the collection. Collapse removes leading and trailing whitespaces, and replaces any sequence of whitespace characters with a single space.
| |
| isDefaultEmptyContainer | back to summary |
|---|---|
| public boolean isDefaultEmptyContainer() Implements org. INTERNAL Return true if an empty container should be set on the object if there is no presence of the collection in the XML document.
| |
| isNormalizingStringValues | back to summary |
|---|---|
| public boolean isNormalizingStringValues() Implements org. PUBLIC: Returns true if this mapping is normalizing string values on unmarshal before adding them to the collection. Normalize replaces any CR, LF or Tab characters with a single space character.
| |
| isWriteOnly | back to summary |
|---|---|
| public boolean isWriteOnly() Overrides org. Implements org. Doc from org. INTERNAL: Some mappings support no attribute (transformation and multitenant primary key).
| |
| isXMLMapping | back to summary |
|---|---|
| public boolean isXMLMapping() Overrides org. INTERNAL:
| |
| preInitialize | back to summary |
|---|---|
| public void preInitialize(AbstractSession session) throws DescriptorException Overrides org. Doc from org. INTERNAL: Allow for initialization of properties and validation.
| |
| setAttributeValueInObject | back to summary |
|---|---|
| public void setAttributeValueInObject(Object object, Object value) throws DescriptorException Overrides org. Implements org. Doc from org. INTERNAL: Set the value of the attribute mapped by this mapping.
| |
| setCollapsingStringValues | back to summary |
|---|---|
| public void setCollapsingStringValues(boolean collapse) Implements org. PUBLIC: Indicates that this mapping should collapse all string values before adding them to the collection on unmarshal. Collapse removes leading and trailing whitespaces, and replaces any sequence of whitespace characters with a single space.
| |
| setDefaultEmptyContainer | back to summary |
|---|---|
| public void setDefaultEmptyContainer(boolean defaultEmptyContainer) Implements org. INTERNAL Indicate whether by default an empty container should be set on the field/property if the collection is not present in the XML document.
| |
| setIsCDATA | back to summary |
|---|---|
| public void setIsCDATA(boolean CDATA) Implements org.
| |
| setIsWriteOnly | back to summary |
|---|---|
| public void setIsWriteOnly(boolean b) Implements org.
| |
| setNormalizingStringValues | back to summary |
|---|---|
| public void setNormalizingStringValues(boolean normalize) Implements org. PUBLIC: Indicates that this mapping should normalize all string values before adding them to the collection on unmarshal. Normalize replaces any CR, LF or Tab characters with a single space character.
| |
| setNullPolicy | back to summary |
|---|---|
| public void setNullPolicy(AbstractNullPolicy value) Implements org. Doc from org. Set the AbstractNullPolicy on the mapping
| |
| setNullValue | back to summary |
|---|---|
| public void setNullValue(Object nullValue) Implements org. PUBLIC: Allow for the value used for null to be specified. This can be used to convert database null values to application specific values, when null values are not allowed by the application (such as in primitives). Note the default value for NULL is used on reads
| |
| setReuseContainer | back to summary |
|---|---|
| public void setReuseContainer(boolean reuseContainer) Implements org. Specify whether the original container on the object should be used if present. If it is not present then the container policy will be used to create the container.
| |
| setWrapperNullPolicy | back to summary |
|---|---|
| public void setWrapperNullPolicy(AbstractNullPolicy policy) Implements org. Doc from org. Set the Wrapper NullPolicy on the Mapping.
| |
| setXPath | back to summary |
|---|---|
| public void setXPath(String xpathString) Implements org. Set the Mapping field name attribute to the given XPath String | |
| useCollectionClassName | back to summary |
|---|---|
| public void useCollectionClassName(String concreteContainerClassName) Implements org. INTERNAL: Used to set the collection class by name. This is required when building from metadata to allow the correct class loader to be used.
| |
| valueFromRow | back to summary |
|---|---|
| public Object valueFromRow(AbstractRecord row, JoinedAttributeManager joinManager, ObjectBuildingQuery sourceQuery, CacheKey cacheKey, AbstractSession executionSession, boolean isTargetProtected, Boolean[] wasCacheUsed) throws DatabaseException Overrides org. INTERNAL: Build the nested collection from the database row.
| |
| writeFromObjectIntoRow | back to summary |
|---|---|
| public void writeFromObjectIntoRow(Object object, AbstractRecord row, AbstractSession session, DatabaseMapping. INTERNAL:
| |
| writeSingleValue | back to summary |
|---|---|
| public void writeSingleValue(Object value, Object parent, XMLRecord record, AbstractSession session) Implements org. Doc from org. INTERNAL: A method that marshals a single value to the provided Record based on this mapping's XPath. Used for Sequenced marshalling. | |